react/example/src/NetworkMonitor.tsx

import React from 'react'
import { useOcean } from '@oceanprotocol/react'
import { ConfigHelper } from '@oceanprotocol/lib'
import { useEffect } from 'react'

export function NetworkMonitor() {
  const { connect, web3Provider } = useOcean()

  const handleNetworkChanged = (chainId: number) => {
    // const config = getOceanConfig(chainId)
      // temp hack
      let network = ''
      switch (chainId) {
          case 1:
              {
                  network = 'mainnet'
              }
          case 4: {
              network = 'rinkeby'
          }
      }
    const config = new ConfigHelper().getConfig(network)
    connect(config)
  }
  useEffect(() => {
    if (!web3Provider) return

    web3Provider.on('chainChanged', handleNetworkChanged)

    return () => {
      web3Provider.removeListener('chainChanged', handleNetworkChanged)
    }
  }, [web3Provider])

  return <></>
}